Faces and stages of dementia

Symptoms of dementia

Dementia is a pattern of symptoms that can be the result of many causes. The pattern of symptoms is heterogeneous both regarding the type (e.g. cognition, behaviour) and severity (mild to severe) of symptoms.

Dementia has several key features:

  1. Cognitive problems: These affect memory, attention, language, spatial orientation and thinking. Memory problems are not always the main problem.
  2. Difficulties in everyday life: At the beginning, complex tasks such as organizing the household or financial planning can be difficult. Later on, even simple things such as preparing meals or getting dressed can become a challenge. In later stages, people with dementia need help with basic tasks such as eating and dressing.
  3. Behavioral abnormalities and psychological symptoms: These include a range of changes such as listlessness, depression, agitation, delusions, aimless wandering, disregard for social rules, impulsivity, overeating, repetitive behavior and nocturnal confusion. These changes are often caused by difficulties resulting from a mismatch between the person's abilities and the demands of their environment.
  4. Physical symptoms: Dementia not only affects thinking and behavior, but can also impair physical functions. In some forms of dementia, physical symptoms appear late, such as incontinence in Alzheimer's disease, while in others they appear earlier, such as Parkinson's-like symptoms in Lewy body dementia or overeating in frontotemporal dementia.

Cognitive symptoms of dementia

Domain Subdomain Example
Attention, concentration Attention
Slowness of responses, drowsiness, sleepiness;
Difficulty focusing on a task, distractibility
Memory Working memory

Episodic memory

Long-term memory
Forgetting the beginning of a sentence at its end;
forgetting a telephone number during dialing

Forgetting recent events or conversations; forgetting the names of people; losing items around the home; repeated questioning; inability to follow plots of movies

Forgetting events that happened years ago
Confusing own biography
Orientation Orientation in time
Orientation in space
Confusing time of day, day of week, year
Difficulty finding rooms, getting lost in unfamiliar surroundings
Language Comprehension

Loss of the meaning of single words; difficulty understanding spoken speech; unable to read

Word finding difficulty; distortion of words
Grammatical errors, effortful or halting speech
Executive functions Abstraction, judgment
Set shifting
Planning, organising
Difficulty using concepts, generalisations, drawing conclusions
Difficulty applying and shifting between rules
Difficulty structuring tasks, following logical steps
Social cognition Emotion recognition

Appropriate response to emotions of others
Lack of empathy

Abnormal social behaviour
Handling objects Single movements

Complex actions
Difficulty performing a movement with a body part despite intact sensory and motor function

Difficulty performing a motor sequence (e.g. opening a can)
Visuospatial abilities Object recognition
Inability to visually recognise familiar objects
Inability to draw or copy simple objects

Stages of dementia

There are different stages of dementia. It begins with subjective cognitive impairment, followed by mild cognitive impairment, in which memory problems occur. Then mild behavioral problems with behavioral changes arise. In mild dementia, the first difficulties occur in everyday activities. In the moderate stage, memory and judgement deteriorate, and finally, in the severe stage, basic everyday activities can no longer be performed alone. As the diagram "Stages of Alzheimer's disease" shows, the onset of dementia can occur 10 to 20 years before the first symptoms appear.

Subjective cognitive impairment

  • The person notices memory problems, although tests show normal results.
  • Increased risk of dementia; regular check-ups are important.
  • May also occur with depression or other health problems.

Mild cognitive impairment (MCI)

  • Intermediate stage between normal age-related changes and mild dementia.
  • Those affected complain of memory problems, but everyday functions are retained.
  • Different cognitive areas can be affected.
  • In around 10 - 12% of cases, mild cognitive impairment progresses to dementia each year. However, the condition can also regress over time or remain unchanged.

Mild behavioral changes

  • Persistent behavioral changes that affect relationships or work.
  • Drive, mood, impulse control and social adjustment may be impaired.
  • May be accompanied by mild cognitive impairment.

Mild dementia

  • Impairment of everyday activities, initially more complex (cooking, shopping, taking medication, diary management), later simpler (personal hygiene, dressing, taking meals).
  • Symptoms vary depending on the cause or form of dementia.

Moderately severe dementia

  • Significant memory problems, impaired judgement.
  • Difficulties with simple everyday tasks.
  • Behavioural changes such as listlessness, restlessness, delusions.

Severe dementia

  • Further deterioration in cognition and behaviour.
  • Sleep disorders, swallowing disorders, incontinence.
  • Increased risk of falls and infection.
  • Often requires round-the-clock care.
  • Positive stimulation remains important (touch, voice).

The transitions between these stages are seamless and the symptoms depend on the cause of the dementia. Early recognition and appropriate support are crucial for the quality of life of those affected and their families.

The severity of dementia can be determined with the help of screening tests. The most common method is the Mini-Mental Status Test (MMST) with 30 points (30 no, 0 severe cognitive impairment). The table shows the categorisation into degrees of severity according to the MMST.

Symptoms at different stages of dementia

Category Mild cognitive impairment Mild dementia Moderate dementia Severe dementia
MMSE Score 30-27 26-20 19-11 10-0
Mean duration [yrs] 5-7 2-3 2-4 2-5
Cognitive symptoms Minor memory problems

Word finding difficulty Poor problem solving

Severe memory loss
Poor judgment
Communication difficulty
Severe memory loss Disorientation
Loss of recognisable speech
Activities of daily living Subtle problems with complex tasks Complex activities impaired (e.g. managing finances) Basic activities impaired (e.g. taking care of hygiene); assistance needed Full-time assistance needed
Behavioural and psychological symptoms None Apathy Depression Social withdrawal Irritability,
Agitation Restlessness, Wandering, Delusions, anger Hallucinations Disinhibition  
Aggressiveness Delusions Hallucinations Restlessness Crying, Shouting

Physical symptoms

None None Incontinence Change in sleep-wake pattern Difficulty walking, eating, swallowing Falls, Seizures
Incontinence Weight loss

The classification into different degrees of severity mainly refers to the most common form of Alzheimer's dementia and not to other forms such as frontotemporal dementia, in which behavioral changes or physical symptoms may occur earlier.

Particular features of different forms of dementia

The different forms of dementia have distinct characteristics that can be used to recognize and classify them:

1. Alzheimer's disease

  • Problems with memory, language, planning, making decisions.
  • Avoidance of demanding tasks and social contact out of shame.
  • Rare insight into the disease - self-protection, as identification with the diagnosis is not possible due to the stigma.

2. Frontotemporal dementia

  • Behavioral changes such as impulsiveness, overeating, weight gain, listlessness, apathy (apathy), inappropriate social behavior such as disinhibition, rigid or compulsive behavior.
  • In the linguistic variant, there is an impairment of the ability to express oneself or understand language.

3. Vascular dementia

  • Slowing down of information processing.
  • Severe mood swings.
  • Cognitive symptoms depending on the brain regions affected.

4. Lewy body disease

  • Movement disorders - striking similarity to Parkinson's disease.
  • Optical sensory illusions.
  • Fluctuating cognitive abilities during the course of the day.
  • Sleep disorders with vivid dreams.

Psychological and environmental causes of behaviour change

Often, behaviour change is caused or aggravated by specific triggers in the environment. In such cases, identifying and addressing these factors may be more appropriate than pharmacological treatment.

  • Too much or too little activity: a person with dementia may be overwhelmed by too many stimuli such as background noise, too many options to choose from, too much activity, confusing environment, several people speaking to them at the same time, a TV or radio constantly playing. On the other hand, lack of activity, understimulation, or social isolation is the other extreme that can cause behaviour change.


  • Caregiver behaviour: acting from a position of authority, patronizing the person, rushing them, and giving orders can make the individual feel unappreciated, unable to make own decision, or even rejected. This may result in resistance or aggressive behaviour. Also, the introduction of an unfamiliar caregiver may initially cause uncertainty, anxiety or even hostility.


  • Changes of routine and environment: These may give rise to agitation, confusion, disorientation and inability to understand why and what is happening.


  • Physical characteristics of the environment: Behaviour change can be triggered by the room temperature being too high or too low as well as by inappropriate lighting, insufficient cues for orientation, and cluttering.
Icon: Smiley with worrying face


The condition of Thomas worsened and his family was unable to continue caring for him at home. Therefore, he was admitted to a 24-hour care facility. However, the transition was not well handled. Not only was the environment new for Thomas, but also routines changed and staff whom he did not know told him when to take a bath, when to eat and when to take medications. Thomas, having problems with expressing his needs verbally, started screaming, threw objects and pushed people away. A psychiatrist was called who prescribed sedative drugs. By looking at things from the perspective of Thomas, adopting a respectful way of communication, providing enough time to adapt to the new situation and applying a non-pharmacological approach the additional medication might have been avoided.


  • Garand L, Dew MA, Urda B, et a. Marital quality in the context of mild cognitive impairment. West J Nurs Res 29: 976-992, 2007
  • Giebel CM, Burns A, Challis D. Taking a positive spin: preserved initiative and performance of everyday activities across mild Alzheimers, vascular and mixed dementia. Int J Geriatr Psychiatry 32: 959-967, 2016
  • Ismail Z, Smith EE, Geda Y, et al. Neuropsychiatric symptoms as early manifestations of emergent dementia: Provisional diagnostic criteria for mild behavioral impairment. Alzheimers & Dementia. 2016;12(2):195-202.
  • Petersen RC, Smith GE, Waring SC et al. Mild cognitive impairment: Clinical characterization and outcome. Arch Neurol 56: 303-308, 1999
  • Petersen RC. Mild cognitive impairment. N Engl J of Med 364: 2227-223, 2011
  • Petersen RC. Mild cognitive impairment. Continuum (Minneap Minn) 22: 404-418, 2016